Carbon black has historically been the reinforcing agent of choice for rubber-based products such as tires and extruded and molded goods. Carbon black, which is produced by the thermal decomposition of oil and natural gases, greatly enhances mechanical strength and resistance to abrasion, and it has been an economically attractive approach to improving the physical properties of rubber products. However, the increasing demand for other oil- or gas-derived petrochemicals combined with a decreasing supply of oil and natural gas has prompted searches for a carbon black replacement. One replacement that is currently available is silica.
Silica has also been used as a reinforcing agent for rubber-based compositions but these compositions require the use of a second coupling agent in addition to the sulfur-curing agent required for the rubber. The additional coupling agent is required to graft the silica to the backbone of the rubber polymer. The addition of a coupling agent leads to increased production costs as well as a decrease in the performance of the silica containing rubber composition. Therefore, what is needed are new reinforcing agents that are able to produce vulcanized rubber articles having physical properties that are comparable or superior to those exhibited by articles containing carbon black and/or silica.